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In ancient Greece, ambrosia was the food of the gods. The same name is given to a malicious quarantine weed – a plant described by the botanist Carl Linnaeus in 1753. The great Swede, of course, could not imagine how much trouble this plant would bring to mankind. So what exactly is ragweed weed?
Biological features
The genus Ambrosia has about 50 species and belongs to the Asteraceae family. The most dangerous are several species that are also found in our country. Among them are bare ragweed, tripartite ragweed and sea ragweed. But the palm, undoubtedly, belongs to ragweed.
- The height of the plant is from 20 to 30 cm, but in favorable conditions it can grow up to 2 m.
- The root system of the plant is a powerful rod, easily penetrates even to a depth of four meters.
- The stem of the plant is pubescent, branches in the upper part.
- Leaves pubescent, pinnately dissected. At a young age, the plant looks like marigolds, which often misleads people, having matured, it looks more like Chernobyl – one of the types of wormwood, for which it got its name.
- The flowers of the plant are unisexual: male – yellow-green, collected in branched inflorescences and female, located at the base of male flowers. It blooms from July to October. The plant produces a lot of pollen, which can be carried by the wind over long distances. Even one weed can give rise to numerous offspring.
- In August, seeds begin to ripen, their number is very large, record holders give up to 40 seeds. Seeds do not germinate immediately. They need a rest period of 000 months to six months. Not only fully mature seeds germinate, but also those that are in waxy and even milky ripeness. Seed germination is very high; they can wait 4 years or more for their time to germinate.
- Favorite habitats of this weed are wastelands, roadsides of roads and railways, landfills.
Photo of ragweed.
And this is a photo of her relative – ambrosia tripartite.
Ambrosia tripartite and wormwood are annuals, and bare-panicle is a perennial and winters well. Here she is in the photo.
The story of
The natural habitat of ragweed is the southwest of North America. Even 200 years ago, even there, it was relatively rare. But population migration made it possible for ambrosia seeds to spread throughout the American continent. Sticking to shoes, they penetrated into new areas. In 1873, this noxious weed appeared in Europe. Its seeds ended up in a shipment of clover seeds from America. Since then, this quarantine plant has continued its victorious march not only across Europe, but also across the Asian continent.
In Our Country, the first ragweed plants were seen in 1918 in the Stavropol Territory. The climate of the south of Our Country suited her quite well, on the wheels of cars she spread farther and farther. Now ambrosia can be found even in the south of the middle lane. Gradually adapting to new growing conditions, it confidently moves north. Distribution map of this noxious weed.
Worth ambrosia
All types of ambrosia are quarantine, i.e. especially dangerous, because they have a large potential area of possible naturalization. Why is this weed so bad?
Harm to humans
Pollen of all types of ragweed is a powerful allergen. The degree of allergenicity of the pollen of any plant is determined by two indicators: the size and the number of allergens that are part of it. Ambrosia pollen is small. Such particles freely penetrate the human lungs. The number of pollen particles that a single plant can produce reaches several billion.
There is an allergenicity index, which determines the strength of the allergen. In ragweed, it has a maximum value of 5. An allergy is caused by a content of 5 units of pollen per 1 cubic meter of air. In order for other types of plant pollen to cause an allergy, their concentration must be much higher. When tested on volunteers, sensitivity to pollen was found in half of the subjects. This is a very high figure. This is what the pollen of this plant looks like when viewed at high magnification.
How does an allergy to ragweed pollen manifest itself?
- Very severe allergic bronchitis, which can be complicated by pulmonary edema.
- Asthma attacks.
- Conjunctivitis.
- Rhinitis.
- Headache.
- Temperature increase.
- Itching itch.
- Itching and sore throat.
- Cross-allergic reaction to a number of foods, such as mustard.
Some people may also experience general allergy symptoms.
- Depressed state up to the development of depression.
- Poor sleep and appetite.
- Decreased attention and concentration.
- Increased irritability.
To prevent allergies from becoming a huge problem, it is better to take preventive measures during the flowering of this weed.
- Do not go out into the fresh air in the morning. And it is better to time the walks to the time when the air humidity is high, which happens after the rain. Most ragweed pollen is thrown into the air from 5 am to 12 noon.
- It is better to dry washed things at home, on the street pollen can easily settle on wet things.
- At night and in the morning, do not ventilate the apartment; the windows in the car must be kept closed.
- After being outdoors, you need to wash your face, wash your hair, rinse your mouth. It is better to rinse the nose by preparing a saline solution.
- Bathe your pets more often, ragweed pollen can also settle on their fur.
- Sun glasses keep pollen out of your eyes.
- Daily wet cleaning is required.
There are sites that monitor the state of ragweed flowering. There is also data on the concentration of pollen from this plant in each region.
The seeds as well as the leaves of this quarantine weed are allergenic and can cause dermatitis. The essential oils that ambrosia secretes provoke a severe headache, the pressure jumps up to hypertensive crises.
Ambrosia damage to plants and animals
Having a powerful root system, this plant absorbs a large amount of water and nutrition from the soil, taking them away from cultivated and wild species growing nearby. In just a couple of years, it depletes the soil on which it grows to such an extent that it becomes unsuitable for further agricultural use. Getting into the crops of cultivated plants, ragweed not only takes away their water and mineral nutrition, but also light, as it grows above them. In cultivated plants, the process of photosynthesis slows down, they are inhibited and even die.
Getting into livestock feed, this weed worsens the quality of milk. It becomes unpleasant in taste and acquires the same smell due to the content of bitter substances in this plant. If you make silage from grass containing ambrosia, the animals do not want to eat it.
How to deal with ambrosia
Why was the ragweed weed able to capture large areas so quickly? This strong and strong plant easily displaces any competitors. A huge number of seeds and their ability to germinate for many years contributes to the rapid reproduction of this quarantine weed. At home, ambrosia has pests and plants that can significantly limit its habitat. But neither in Europe nor in Asia they are not. Ambrosia can only compete with some weeds that live next to it. Among them are couch grass and pink thistle. These plants are able to significantly reduce the height of ragweed plants, as well as the number of seeds that it can form.
In order to defeat this weed that is dangerous to humanity, it will take the joint efforts of not only specialists, but also ordinary people.
Foci of ambrosia in Europe.
In Europe, there is already a large-scale project that provides for the environmentally sound protection of agricultural plants. 200 researchers are looking for insects and plants that could cope with the biological expansion of ragweed. 33 states have already joined the project. It is called SMARTER for short. The project was initiated by the Swiss ecologist Professor Heinz Müller-Scherer. In Our Country, there are regional programs that are aimed at combating this malicious weed.
Control measures
- The most productive method of dealing with ragweed in private ownership is manual. Moreover, mowing is effective only during the period when the plant begins to bloom. If this is done earlier, the effect will be the opposite, since the number of shoots of the plant will multiply many times over. You will have to repeat the mowing of ambrosia until the end of the vegetation of the plant in late autumn. For ragweed, this method of struggle is ineffective, since it is a perennial plant.
- Manual weeding of the weed before the formation of seeds gives a very good effect. The plant may completely disappear from the site.
- Chemical methods for the destruction of harmful weeds. To treat fields with soybean crops, the herbicide Bazagran is used, which is also used in a mixture with another herbicide, titus, on corn crops. The consumption rates of herbicides for the effective destruction of the weed are quite high, which does not contribute to the improvement of the environment. Herbicides Secateur and Hurricane are also used. The best results are obtained by a mixture of these herbicides, the time of its application is the beginning of flowering of the ragweed. Such a mixture allows you to reduce the concentration of both substances without reducing the effectiveness of the treatment. Ambrosia does not respond well to herbicide treatment. When processing, you need to use a protective suit and a respirator.
- Using the method of displacing ragweed with mixtures of cereals and legumes. A good result on farmland gives the correct crop rotation, careful care of crops. There is information about the use of its natural enemies brought from America, namely the ragweed leaf beetle Zygogramma suturalis and the cutworm butterfly Tarachidia candefacta, to combat this quarantine weed. Experiments with the use of these insects are encouraging. This method of fighting ragweed is successfully used in China.
The ragweed leaf beetle is the brother of the Colorado potato beetle, but unlike it, it does not recognize any other food, therefore it does not pose a danger to other plants. Since the 80s of the last century, the time when the zygogram beetle was first released into the fields to combat ragweed, amazing metamorphoses have taken place with it. He not only changed his color, but also learned to fly, which he could not do in his homeland. It took only 5 generations of the zygogram to grow wings. The reproduction of the beetle is hindered by crop rotation, due to which it does not have a permanent habitat.
It cannot be said that, on the basis of ambrosia, quite effective medicines have been created for certain diseases, which, oddly enough, include allergies.
The uncontrolled spread of such a dangerous weed is a side effect of the human development process. It was thanks to the improvement of communication links that it became possible not only to move this plant to other continents, but also to quickly spread within them.
